Erbium Doped Fiber Optical Amplifier (EDFA) modules and/or subassemblies used in optical communication networks generally include multiple elements such as erbium doped fiber, isolators, monitor taps, photo detectors, pumps, wavelength division multiplexers or combiners, splitters, etc. In order to properly control module and/or subassembly based on difference system configurations, the module and/or subassembly must have calibration data, configuration data, and the like. There are two conventional methods to achieve properly EDFA module and/or subassembly control—a “smart” EDFA module and/or subassembly with a built-in control circuit and a “dumb” EDFA module and/or subassembly without a control circuit. The smart EDFA module and/or subassembly with the built-in control circuit has all calibration data stored within the module and/or subassembly. A communication interface such as an RS232 serial data link or an Inter-Integrated Circuit (I2C) provides communication between a host module (system) and the module and/or subassembly. The host module, based on a system configuration, sets a desired control power level command. The smart EDFA module and/or subassembly, based on the command, accesses the data retaining device to retrieve the corresponding data to finish power level control. The dumb EDFA module and/or subassembly without the control circuit requires the host module for accessing data. In this method, the host module (system) stores all calibration data and a circuit on a host board accesses the data retaining device to retrieve the corresponding data to finish power level control.
In actual implementations, the smart EDFA module and/or subassembly, for different suppliers, the implementations significantly differed between suppliers thereby leading to difficulty in EDFA controlling behaviors. This makes system validation more complicated and in some cases software and hardware defects can take several years to show up and become fully understood. For systems-based integrators and manufacturers, the dumb EDFA implementation is more suitable since integrators and manufacturers define the system and integrators and manufacturers more clearly understand the system requirement. The dumb EDFA implementation can minimize hardware and software defects. A mistake can be easily and quickly found. The hardware and software design can be inherited for future EDFA modules and/or subassemblies.
However, dumb EDFA implementation is very labor intensive especially for advanced optical system where multi-pumps, multi-photo-detectors, and multi-variable-optical-attenuators are used. This can lead to several hours required to fully calibrate the EDFA. A dumb gain block purchased from supplier typically already has been tested and some calibration data is available in a database but not with a dumb EDFA module and/or subassembly.